Thermostatic controlling mechanism for water-heaters.



C. A.BACKSTROM.. -THERMOSTAUC CONTROLLING MECHANISM FOR WATER HEATERS.

APPLICATION HLLD SEPT. $3, 1915.

Patented Out. I, 1919.

i N N N N N N N N N UNEETED STATES PATENT @FFMEE.

CHARLES A. BACKSTROM, 0F GRAFTON, PENNSYLVANIA, ASSIGNOR T0 PITTSBURGl'WATER HEATER COMPANY, OF YITTSBURGH, PENNsYLVANIA, A CORPORATION OF NEWJERSEY.

THERMOSTATIC CONTROLLING MECHANISM FOR HATER-HEATERS.

To all whom it may concern:

Be it known that I, CHARLES A. BACK- s'rRoM a citizen of the UnitedStates, residing at Grafton, in the county of Allegheny and State ofPennsylvania, have invented certain new and useful Improvements inThermostatic Controlling Mechanism for lVater-l-leaters, of which thefollowing is a specification.

The invention relates to thermostatic controlling means for waterheaters of the storage or other types. objects; the provision of athermostatic controlling means which will give rapid opening and closingmovements of the gas valve and in which the periods of low burning arereduced to a minimum, it being well known that low burning is wastefulof gas and hard upon the burners; the provision of a simplifiedmechanism for accomplishing the result above stated in which thecomplication incident to the use of the so-called snap valve mechanismnow in use is eliminated; and the provision of a thermostatic controlwhich is sensitive and not liable to et out of adjustment. Oneembodiment of the invention is shown in the accompanying drawing,wherein- Figure 1 is a full sized section through the Controllingmechanism constituting my invention, certain of the other cooperatingparts being shown diagramnnitically in dotted lineaFig. 2 is a sectionalview show ing the ball valve in the position of fullest opening, andFig. 3 is a view similar to that of Fig. 2, but with the valve partiallyclosed, although stilladmitting a maximum flow of gas.

My invention depends in part upon the fact that the eli ect from athermostatic element and its auxiliaries as used in a water heater ismost rapid during the latter portion of its movements, and I so arrangemy apparatus that the gas valve is affected by these means to open andclose during the periods of rapid movement. To this end I so arrange theoperating parts of the thermostatic means that on the opening opera tiona considerable movement thereof occurs before the gas valve is engaged,the opening of the valve after such engagement being comparativelyrapid. Further, the parts are so arranged that in the opening movementSpecification of Letters Patent.

Application filed September 13, 1915.

Ithas for its primary a part of the gas conduit.

racemes Get. '2'. late.

Serial No. 50,315.

of the valve such valve is moved oft its seat 'to a, distance greaterthan that required to give a maximum flow of gas to the burners, so thaton the reverse movement of thermostatic parts the throttling of the gasdoes not commence until the valve is-partially closed and thethermostatic parts are well under way in their movement, the cutting oilof the gas thus being quickly accomplished after the actual throttlingmovement of the valve starts. In other words, I provide for an overtravel of the thermostat with respect to the gas valve in bothdirections, thus giving periods of complete cut off after the closingmovement, in addition to the quick action of the valve.

In the drawing, 1 is the casin which carries a part of the mechanismant, constitutes 2 is the gas inlet and 3 is the outlet leading to theburner 4 beneath the shell 5 of the water container.

The thermostat consists of the usual cop per tube 6 projecting into thewater container and carrying at its inner end the plug 7 against whichthe inner end of the porcelain rod 8 abuts, the other end of the tube 6being screwed into the coupling 9 to which the casing 1 is attached. Theleft hand end of the rod 8 bears against. the slidable plug 10 in whichis mounted the pin 11. From this it will be seen that as the temperatureof the water in the heater rises the tube 6 will expand to the right andpermit the parts 8, 10, and 11, to move to the right, and when theten'iperature ot the water drops the tube 6 will contract and move theparts specified above to the left.

The controlling valve is in the form of a ball 12 held against its seat13 by a spring 14, so that. when the valve is not otherwise acted uponit is yieldingly seated by gravity and by the force of the spring.Interposed between the valve and the operating pin 11 is the multiplyingdevice consisting of the levers15 and 16 and the connecting link 17 towhich the right hand ends of the levers are pivoted, these parts beingsupported upon the adjustable frame piece 18 having its left hand endfitting in the plug 19 and its right hand end 20 fitting in the coupling9. The frame piece is held in position. in the plug 19 by means of thethreaded rod 21. The plug is locked in position by v 3/16 inches.

means of the nut 22, the outer end of the plug being made in the form ofa nut 23 so that it can be adjusted. The. pin 21 is locked in positionby means of the thumb screw 24, and the extreme outer end of the pincarries a nut 25 which serves to lock the protecting cap 26 in position.The adjustment of the thermostat and the point of cut off isaccomplished by the adjustment of the frame piece 18, The lever 16 ispivoted to the frame piece at 27, and the lever 15 at 28, such lever 15being provided with an upturned end 29 adapted to engage the valve 12. Aspring 30 bears against the end of the plug 10 and serves to move theplug and the porcelain rod 8 to the right as the tube 6 expands, thusrelieving the spring 14 of this work.

Fig. 1 illustrates the relative position. of the valve and the end 29after the valve has been closed and the lever 15 has moved to its lowestposition. At this time the space 0 between the ball and end in thespecific embodiment illustrated is approximately As the water coolsincident to the cutting off of the gas supply the tube (3 contracts tothe left, thus moving the end 29 upward, the multiplication incident tothe use of the levers illustrated being about to 1. This upwardmoven'ient does not cause the unseating of the valve until the distanceC has been traversed, and when the engagement of the end 29 with thevalve actually occurs the movement is much more rapid than "at thebeginning, and the valve is raised at a comparatively rapid rate. ItWill also be noted that in the period before the engagement of the valveby the end the valve remains seated so that no low burning occurs duringthis period.

The upward movement of the valve is continued until it reaches theposition indicated in Fig. 2, at which time the valve has moved upwardthe distance indicated at A, such distance in the present embodimentbeing )proxin'iately 3/16 inches. The opening a t us provided gives anadmission area in excess of the carrying capacity of the gas conduit, sothat the valve is open farther than is necessary in order to give theburners their maximum amount of gas. The amount of opening necessary togive the burners their maximum quantity of gas is illustrated at B inFig. 3, the distance B being fi/li-l inches. The valve can thereforemove from the position of Fig. 2 to the position of Fig. 3, a distanceof T/Gt inches, without any throttling of the gas and without any lowburning.

lVith the valve in the position of Fig. 2, the water soon reaches itsmaximum temperature and the tube 6 expands to the right, permitting theend 29 and the valve 12 to move down, such movement being caused bygravity and by the springs 14 and 30. By the time the valve 12 reachesthe position of Fig. 3 the parts are moving rapidly, so that themovement of the valve from the position oi. Fig. 3 to the position ofFig. 1 occurs rapidly and the period of low burning is relatively short.2

It will be seen from the foregoing that the arrangement provides for therapid opening and closing of the "as valve, thus reducing the periods oflow burning, and that there is a period of some length when the partsare moving from the position of Fig. 1 to a position in which the end 29engages the valve, in which there is a complete cut off of the gas. Thequick movement of the parts is further facilitated by the use of thespring 30 which takes the strainof moving the thermostatic parts oil' ofthe multiplyingdevice and the spring ll. The parts of the multiplyingdevice can be made relatively light, which increases the sensitiveness.and the strain upon these parts is so slight that even with a largemultiplication there is no tendency to gct out of adjustment. Otheradvantages incident to the construction will readily occur to thoseskilled in the art.

\Vhat I claim is:

In con'ibination in a heater having a water container and a gas burner,a gas supply conduit, a valve in the conduit, a thermostat, amultiplying device having its last element which operates the valvemovable with the expansion and contraction of the thermostat parts andat a speed having a fixed ratio to that of said thermostat parts at alltimes, such element being arranged to move the valve in opening it to anextent greater than that necessary to give a capacity equal to that ofthe conduit, the valve being moved only during the latter part of themovement of the therniostatically controlled multiplying device, andbeing arranged, on its reverse mowmcnt, to effect no throttling of thegas during the first part of such reverse movement.

CHARLES A. BACKSTROM.

